120 bullets for Glock pistol
Buy a MP5 and all its bullets, then buy a Glock Pistol. Note: If you already have it, you do not have to buy another one.

120 bullets for Steyer TMP
Buy a MP5 and all its bullets, then buy a TMP.

Sniping Ak47
Aim the crosshair in the middle of the enemy and shoot the bullets two by two. When the crosshair becomes large, run and reload. The target should be dead after you shoot the first two bullets.

Silent AWP shots
in the console, type 'bind mouse1 "+attack; impulse 100" ' then press enter. Voila, now when you shoot your AWP or any sniper rifle, your shots will be silent. Be warned, if you try this with a full-auto weapon, chances are you will be killed as the weapon might jam and stop shooting.

Temporary invincibility
Type bind "setinfo model ../oranget" during game play. Keep pressing the key that was bound to that command to become invincible.